1. Field of the Invention
The present invention relates to a power supply controller for use with semiconductor fabrication facilities, and more particularly, to a power supply controller capable of controlling the amount of AC power supplied to a semiconductor fabrication facilities in accordance with processing conditions therein.
2. Description of the Related Art
Semiconductor fabrication facilities have several types of diffusion furnaces that may be powered by a back-up power supply, in the event there is a power interruption in the commercial power lines delivering electrical power to the facilities. The back-up power from the back-up power supply is of relatively low capacity compared to the electrical power from the commercial power lines.
FIG. 1 is a block diagram of a conventional AC power supply controller for use in a semiconductor fabrication facility. As shown in FIG. 1, a main power supply 80 is connected to commercial electrical power line 100 for delivering AC electrical power to the facilities. A back-up power supply 110 delivers back-up power to the semiconductor fabrication facility in the event of electrical power failures. Power interruption detector 90 detects the power interruption in the commercial power line 100 and generates a power interruption signal. The back-up power supply 110 delivers the back-up power through the main power supply 80 to the facilities in response to the power interruption signal.
Electrical power from the main power supply 80 is delivered through power supply units 20, 40 and 60 to semiconductor fabrication facilities 30, 50 and 70 by means of a main controller 10, respectively. The main controller 10 detects whether the respective facilities require power and generates power control signals in response thereto. The first, second, . . . , and N-th power supply units 20, 40 and 60, which are electrically connected with first, second, . . . , and N-th facilities 30, 50 and 70, are selectively switched on in response to the power control signals from the main controller.
In the conventional power supply controller having the above described construction, the maximum amount of electrical power from the main power supply 80 continues to be delivered to the facilities requiring electrical power, regardless of processing conditions of the facility, that is, the power consumption conditions of each facility.
For example, as shown in FIG. 2A, if the first facility 30 is in a stand-by mode, the second facility 50 in a ramp-up mode, and the N-th facility 70 in a process mode, all of the respective facilities require electrical power. Accordingly, maximum electrical power (i.e., 100% power) from the main power supply 80 is supplied to the respective facilities, as shown in FIG. 2B, by the power supply units 20, 40 and 60.
If the facilities are in an off mode or a ramp-down mode, they do not require electrical power. For example, when a impurity diffusion apparatus is used at a facility, a diffusion tube thereof is heated during the ramp-up mode using maximum electrical power to attain a high internal temperature. Ramp-down mode refers to the situation where the diffusion tube is powered-off so as to have a low internal temperature.
During the stand-by mode or the process mode, each facility requires about 50% of the electrical power, as compared with the maximum electrical power consumption required during the ramp-up mode. However, it can be seen from FIGS. 1 and 2B that the conventional power supply controller of FIG. 1 delivers maximum electrical power to each facility, regardless of the power requirements dictated by the processing conditions in the respective facilities. Accordingly, when the conventional power supply controller is provided for three facilities, the maximum electrical power consumption required for the three facilities is equal to or less than about 300%.
In the event the main power supply is interrupted, if the back-up electrical power is simultaneously supplied to all of the facilities, an electrical power failure may result due to the limited power capacity of the back-up power supply 110. Such a occur. Such a power failure affects the electrical characteristics of the semiconductor device being produced.